Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
SYSTEM AND METHOD FOR AN INTERVERTEBRAL IMPLANT
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the priority of previously filed national
applications:
US Ser.No. 10/947,661 filed in US on Sept. 23, 2004,
US Ser.No. 10/996,797 filed in US on Nov. 26, 2004.
1o of the US Provisional Application US Ser.No. 60/640,106 filed in US on Dec.
30, 2004 and of PCT/IB2005/052041 filed in Geneva on June 22, 2005.
The entire contents of which are hereby incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
The invention relates to a system and method for an intervertebral implant, in
detail a trial implant for the preparation of an intervertebral space for
insertion of
an intervertebral disc prosthesis, to an implant for insertion into this
prepared
intervertebral space; to a chisel for use with an implant or a trial implant
for
preparation of the intervertebral space, to a pre-trial implant for
radiographic
and geographic orientation in the intervertebral space; to a device for
keeping
an intervertebral space open for discectomy and/or for the insertion of an
implant, trial implant or pre-trial implant; to a mounting instrument for
mounting
an intervertebral disc implant having a superior and inferior implant plate
and an
inlay; to an inserter for inserting a trial implant or an implant into the
intervertebral space; and to a method for positioning and fixing an
intervertebral
implant in the intervertebral space.
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DESCRIPTION OF THE PRIOR ART
Implants having at least one upward- or downward-projecting keel are
frequently
used as intervertebral implants. For receiving at least one keel of an implant
in
the superior or inferior vertebra, a groove is usually chiselled by means of a
chisel for each keel. A pre-trial implant or a trial implant can be used in
the
intervertebral space in the conventional manner for radiologic or spatial
orientation. In order to keep an intervertebral space open for discectomy
and/or
1o for insertion of an implant, trial implant or pre-trial implant, struts are
customarily
used and are mounted on the outside of the vertebra.
Known implants for insertion and the method for direct oblique anterior
preparation of an intervertebral space have been publicized under the name
Prodisc (brand of Spine Solutions) both for the lumbar spinal region and for
the cervical spine region and have been successfully launched on the market.
Under the title "Instrument and Method for preparing an intervertebral space
for
receiving an artificial disc implant", patent applications related to the
tools or
instruments and the method for the preparation of an intervertebral space for
insertion of an artificial disc implant directly from the anterior were filed
on
2003-04-03 as U.S. application serial no. 10/023,879 and subsequently as
PCT/USO4/12664. The intervertebral implant Prodisc currently on the market
corresponds substantially to the content of this Patent Application.
Furthermore, patent applications related to the instruments required for
Prodisc and the method for insertion of the intervertebral implant were filed
title "Instruments and method for inserting an intervertebral implant" on 2003-
07-
02 as U.S. application serial no. 10/622,803 and subsequently as
PCT/US04/22608. The Prodisc system corresponds substantially to the
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content of the Patent Application.
Prodisc is described in the brochures of Spine Solutions as "Cervical Total
Disc Replacement" for the cervical spinal region and as "Lumbar Total Disc
Replacement" for the lumbar spinal region:
Brochure "Prodisc-L", with the publication designation SMT 001 G -03/03 and
also SMT014-04/04 describes how the form and function of an intervertebral
disc can be substantially restored by insertion of an intervertebral disc
io prosthesis from the anterior.
The instruments required for this purpose and the surgical technique are
described:
= creation of an access to the two affected vertebrae;
= removal of the intervertebral disc (discectomy) from the intervertebral
region;
= determination of the implant size, implant height, angle of lordosis and
implant position by means of a trial implant by the exact central
orientation thereof with radiographic monitoring;
= precutting of grooves simultaneously from above and below, directly from
the anterior direction, by means of a fork-shaped double chisel guided in
the trial implant;
= insertion of the upper (superior) and lower (inferior) implant plates, the
inferior and the superior plates simultaneously being mounted in the
predetermined position without distraction.
= With the aid of an inserter, the two adjacent vertebrae are forced apart
and
= by means of a pusher the PE inlay is pushed into the inferior plate and
securely locked;
= the instruments are removed and the final implant position is checked by
means of radiographic monitoring.
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Brochure "Prodisc-C", with the publication designation SMT013-04/04,
describes how the form and function of a cervical spine is substantially
restored
by insertion of a cervical intervertebral disc prosthesis:
= First, fixation of the cervical vertebra to a holder by means of screws and
subsequently discectomy are carried out, and the intervertebral space is
held apart by means of a spreading forceps.
= A trial implant having an adjustable stopper is inserted, and, guided by a
fork-like chisel, a groove is then simultaneously chiselled directly from the
anterior direction into the superior and inferior cervical vertebrae.
= The already completely assembled implant is then inserted into the
cervical intervertebral space by means of a special inserter.
In the brochure PRODISC "Retrospective Clinical Study: 7 to 11 Year Follow-
Up" published with the number SMT 002E-03/06, the aims, the method and the
results of these implant techniques are summarized with a conclusion:
All implants (61 out of 64) which were inserted within a period of 7-11 years
were intact and functioned properly.
There was a substantial reduction in back pain and leg pain, and 92.7% of the
patients were very satisfied with the insertion of the prosthesis.
Both Prodisc products and the associated instruments have already been
tested and have been very well accepted by the patient. The mobility of the
spine was completely restored in many cases.
Also known is PCT publication WO-2004/080355A1 "Articular disc prosthesis
for anterior-oblique insertion", which describes an intervertebral disc
prosthesis
for anterior/lateral-oblique insertion. A product of Medtronic "Maverik"
corresponds to an embodiment of this published Patent Application. "Maverik"
is an intervertebral disc prosthesis which - after corresponding preparation
of
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the intervertebral space- can be inserted from the oblique anterior/lateral
direction at an angle of 30 .
This PCT publication WO-2004/080355 teaches that insertion can be effected
5 from the lateral direction. In the case of the insertion direction chosen
for
"Maverik", however, the fact that lateral insertion leads to a change of the
footprint, i.e. to a change of the sagittally visible base surface of the
implant,
was overlooked. In comparison with known implants which permit oblique
anterior insertion, "Maverik" is smaller and approximately triangular. This is
1o evidently associated with its insertion direction of 30 . However, a
smaller
footprint means in certain circumstances poorer anchorage of the prosthesis in
the vertebra. On consideration of the PCT publication together with "Maverik",
a
person skilled in the art would, however, therefore generally be discouraged
from choosing an oblique anterior/lateral access. The footprint reduction and
poorer fixing associated therewith appear seriously disadvantageous to a
person skilled in the art.
Furthermore, publication WO-2004/080355A1, at Fig. 40 showed a figure with
an angle of about 52 to the AP direction, measured from the figure. In
publication WO-2004/080355A1, this angle is about 37 in Fig. 44a. The fact
that Medtronic, which is associated with SDGI, actually markets and delivers
its
product "Maverik" with only 30 is understood by the person skilled in the art
to
teach departure from the originally disclosed access angle of about 52
through
about 37 to 30 . To the person skilled in the art, however, this means that
the
implant area must be reduced in order to bypass the vessels without risk of
injury (oblique access). This is the teaching of this WO publication in
conjunction
with the product "Maverik".
Evidently, in the choice of the angle at the time of the development of
Maverik,
the persons skilled in the art did not regard an angle between 52 and 37 as
optimal, but rather an angle of about 30 which is not even described in
WO-2004/080355A1, and accepted the effect with footprint reduction.
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Another patent publication, EP1259175B1, relates to "Instruments for disc
space preparation". It discloses a medical instrument for the preparation of
an
intervertebral space between adjacent vertebrae of a patient. A cutting edge
guide is designed so that it has a distraction holder for maintaining
distraction
between the two vertebrae. A blade channel has a guide channel which is
designed so that it can receive a guide rib at or on a cutting edge in order
to
maintain the orientation of the cutting edge relative to the holder and hence
relative to the vertebrae.
U.S. published application no. 20040199168 discloses instruments and
methods for the positioning of one or more implants in a spinal intervertebral
space. The instruments and methods are designed for oblique insertion
laterally
relative to the intervertebral space. The instruments include a distractor,
and a
guide to permit positioning of one or more implants in the intervertebral
space.
SUMMARY OF THE INVENTION
One object of the invention is the provision of novel intervertebral implants,
of a
novel improved method and of the associated instruments or of devices for the
preparation of an intervertebral space and for the insertion of an
intervertebral
implant, in particular for the lumbar spine.
According to another object, the method of the invention is intended to permit
oblique anterior/lateral insertion at an angle of about 45 , in particular
left
oblique-anterior insertion, viewed from the patient.
A trial implant according to a version of the invention may be inserted into a
prepared intervertebral space. It serves for determining the size and position
of
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the implant to be inserted. The trial implant may be oriented radiographically
by
means of sighting slots according to the invention, and simultaneously serves
as
a guide for a chisel. A chisel may be used for chiselling, into the
intervertebral
surface of the superior and inferior vertebrae, a respective groove each of
which is normal to the intervertebral surface so that an implant insertable in
exchange for the trial implant and having a corresponding keel rests as flat
as
possible on the vertebral surface. The trial implant has a superior and an
inferior
contact surface with at least one guide slot each which guides the chisel in
at
least two directions in space.
The keel of the implant may be fixed thereto or, according to a version which
may be used independently of the above, may be mounted rotatably relative to
the contact surface, with subsequent fixing in the contact surface.
According to a version of the invention, the chisel is in the form of a mono-
chisel, and is guided in the trial implant or in the implant. For the
preparation of
the intervertebral space, in particular for radiographic and spatial orientati
i on in
the intervertebral space, a pre-trial implant according to the invention may
also
be used.
In order to keep the intervertebral space open for a discectomy and/or for
insertion of an implant or trial implant, leaf-like struts according to the
invention
are used and are inserted in the proximal area of the intervertebral space-
preferably to the side of a trial implant - and run in a wedge shape at the
angle
of lordosis and may be curved medially at their medial end in order to improve
the vision of the operating area. These novel struts may also be used
independently of the above. The struts may be individual struts which can be
inserted into the intervertebral space. For mounting of an intervertebral disc
implant with a superior and inferior implant plate and an inlay according to
the
invention, a mounting instrument is used by means of which the exactly fitting
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implants may be assembled from a group of implant plates and inlays directly
in
the operating theatre. In a certain embodiment of the invention, an inserter
according to the invention for the trial implant or for the implant serves for
the
insertion into the intervertebral space. The positioning and fixing of the
intervertebral implant or of the trial implant for preparation is effected in
the
intervertebral space preferably at an oblique anterior, in particular left
oblique
anterior, angle, according to the invention at an angle of about 450 to the
medial
plane (anterior-posterior plane), viewed from the patient.
1o According to a version of the invention, a special assembly device, by
means of
which the inlay can be placed in the correct position in the implant plate or
locked with it, is used for assembly of the implant.
According to a version of the method of the invention, an inserter is used for
inserting the trial implant or the implant, it has a retaining mechanism for
an
implant collet, which is passed through a rod to an actuating part having a
locking lever by means of which the implant can be held or released.
According to a version of the invention, the implant can be inserted all in
one, or
first the upper and lower part followed by the inlay. Before and during the
insertion, the intervertebral space is held open by the struts according to
the
invention.
In a preferred version, the invention starts from an optimum "footprint" with
an
insertion direction of about 45 giving de facto this abrupt improvement
effect at
45 with the largest possible footprint in spite of anterior/lateral access.
Some particular advantages resulting from the oblique insertion at about 45 :
= The main blood vessels running on the anterior side of the spine are less
extended during the operation;
= this results in easier access than the direct oblique anterior access.
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= It makes it possible to bypass the complex vessel structure
(stomach/intestine) which is present directly in front of the vertebrae.
= Although the lateral approach is already known per se through "Maverik",
the insertion angle there is 300 relative to the anterior-posterior plane.
However, owing to the disadvantage of the footprint reduction of this
known lateral insertion method, the inventors were discouraged from
applying it further since they attached considerable importance to the
footprint size or the optimum adhesion between the vertebrae and the
implant.
= Through inventive considerations and experiments on the part of the
inventors, it was surprisingly found that an insertion angle of about 45
during insertion of the implant proves to be optimum with regard to the
best possible footprint - with a simultaneously advantageous access.
According to a version of the invention, particular attention is also devoted
to the
preparation of the intervertebral space by means of a trial implant and the
exact
chiselling of the groove for receiving the implant keel at 90 to the
respective
intervertebral surface. This ensures very good retention of the implant.
Although the drawings also show the preferred embodiments, neither the
drawings nor the description are to be interpreted as being restricted. On the
other hand, contents of the drawings and of the description as well as the
contents of the patent claims belong to the disclosure of the invention in
this
patent application. These and other features, aspects, and advantages of the
present invention will become better understood with regard to the following
description, appended claims, and accompanying drawings.
For better preparation for an intervertebral disc prosthesis, a novel trial
implant
was developed for the preparation of the intervertebral space, having a
superior
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and inferior bearing surface and having one guide slot each in the superior
and
inferior bearing surface, at least one of the guide slots being formed in such
a
way that an insertable or inserted guide can be held or is held
nondisplaceably
in two directions in space- in particular parallel and normal to the
respective
5 bearing surface. A movement of a guide in the longitudinal direction
relative to
the guide slot is thus possible. Owing to the novel formation according to the
invention, for example, the use of a monochisel instead of a fork-like chisel
is
possible. However, this novel guide slot in the trial implant also makes it
possible to locate other tools and devices relative to the trial implant.
A further development of the trial implant in which the guide slot serves for
guiding the chisel is characterized in that the chisel is in the form of a
monochisel which is connected to a guide which is displaceable relative to it
and is formed diametrically oppositely to the respective guide slot. The guide
projects beyond the chisel in the longitudinal direction. The guide thus
permits
the positioning of the chisel relative to the trial implant and hence to the
vertebra
even before it touches the vertebra.
According to a particular further development of the invention, the two guide
slots (one each in the superior and in the inferior implant plate) are in
different
three-dimensional positions relative to one another (angle f3). This makes it
possible for the trial implant in cooperation with the chisel to enable
preparation
of a groove from the oblique anterior/lateral direction. It is also possible
to
provide a plurality of guide slots per plate.
A development according to the invention which is independent of the above
and of course may also preferably be used together therewith relates to a
trial
implant for the preparation of an intervertebral space for use of an
intervertebral
disc prosthesis, having a superior and inferior bearing surface and having at
3o least one groove each in the superior and inferior bearing surface, at
least one
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of the grooves being in the form of a sighting slot so that, in the case of a
trial
implant inserted into an intervertebral space under radiographic monitoring,
it
enables detection of the position thereof relative to the vertebra. This
ensures in
a simple manner that a surgeon can perform the correct orientation of the
trial
implant under radiographic monitoring, and the subsequent position of the
implant can thus be well prepared.
This is particularly simplified if the sighting slot is at that angle (?) or
at a
complementary angle (d) to the respective guide slot, which corresponds to the
1 o surgical approach angle (e) or the direction of insertion of the implant
into the
intervertebral space for the implantation of an intervertebral disc
prosthesis.
In order to permit an all round positioning check by means of X-rays guided by
a
C-arc, a further development provides, per bearing surface, two sighting slots
which are at a right angle to one another.
In principle, all materials tolerated by the body are available for the choice
of
material, but it is advantageous if the trial implant is composed of X-ray-
opaque
or X-ray visible material. In the case of this design, the sighting slots are
as a
2o rule produced by milling and are open to the outside. However, they can
also be
filled with X-ray-transparent material, for example plastic. The trial implant
can
thus also be plastic-coated (e.g. polyethylene), which permits an integrated
surface and improved sliding properties on the insides of the vertebrae.
Alternatively, the trial implant may also be composed of X-ray-transparent
material, X-ray-opaque or X-ray-visible inlays being provided instead of the
sighting slots. In the case of this alternative design, the X-ray visibility
effect or
the positioning aid is further simplified if the guide slots, too, are X-ray-
visible.
3o An invention which is independent of the above but which is preferably used
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together with the above constructions comprises providing, on the lateral
surface, at least one impact hollow for the engagement of an impact bar in the
case of a trial implant for the preparation of an intervertebral space for
insertion
of an intervertebral disc prosthesis, having a superior and inferior bearing
surface and having a lateral surface. These novel impact hollows permit secure
attachment of impact bars guided by the surgeon's hand. A trial implant can
thus
be precisely positioned.
According to a further development, a guide shank intended for engagement of
1 o an impact shank or handle likewise serves for positioning and also for
removal
of a positioned trial implant according to one of the preceding designs.
According to a further embodiment, an adjustable stop serves for limiting the
depth of penetration of a trial implant into the intervertebral space.
According to the novel insertion method according to the invention, the trial
implant is preferably formed for insertion from about 45 relative to the
medial
plane (anterior-posterior plane) between two vertebrae.
2o The invention also comprises a novel implant for use as an intervertebral
disc
prosthesis in an intervertebral space, having a superior and inferior bearing
surface and having at least one guide slot each in the superior and inferior
bearing surface, at least one of the guide slots being formed in such a way
that
an insertable or inserted guide can be held or is held nondisplaceably in two
directions in space - in particular parallel and normal to the respective
bearing
surface. Such an implant makes it possible to avoid the use of a trial implant
and thus to accelerate the operation process. However, its use will require
even
further tests so that the application is currently not yet preferred.
In any case, this guide slot - as in the trial implant - may serve for guiding
a
chisel, the chisel being in the form of a monochisel which is connected to a
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guide which is displaceable relative to it and is formed diametrically
opposite to
the respective guide slot and projects longitudinally beyond the blade of the
chisel.
As in the case of the trial implant, the two guide slots may be in a different
three-
dimensional position relative to one another (angle R).
The invention also comprises a novel implant for use as an intervertebral disc
prosthesis in an intervertebral space and for the preparation of the
intervertebral
1o space, having a superior and inferior bearing surface and having at least
one
groove each in the superior and inferior bearing surface, at least one of the
grooves being in the form of a sighting slot so that, in the case of an
implant
inserted into an intervertebral space, said groove enables its position
relative to
the vertebrae to be detected radiographically.
This is particularly simplified if the sighting slot is at that angle (?) or
at a
complementary angle (d) to the respective guide slot which corresponds to the
surgical approach angle (e) or the direction of insertion of the implant into
the
intervertebral space for the implantation of the intervertebral disc
prosthesis.
In order to permit all round positioning guided in the form of an arc, two
sighting
slots, which are at a right angle to one another, are provided per bearing
surface.
In principle, all materials tolerated by the body are available for the choice
of
material, but it is advantageous if the implant is composed at least partly of
X-ray-opaque or X-ray-visible material. Instead of the sighting slots, X-ray-
opaque or X-ray-visible inlays may be provided, the guide slots being X-ray
visible.
In a further embodiment of an implant according to the invention for use as an
intervertebral disc prosthesis in an intervertebral space and for the
preparation
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of an intervertebral space for use of an intervertebral disc prosthesis,
having a
superior and inferior bearing surface and having a lateral surface, at least
one
impact hollow for engagement of an impact bar is provided on the lateral
surface. These novel impact hollows permit secure attachment of impact bars
guided by the surgeon's hand. The implant can thus be precisely positioned.
The implant preferably has a removable guide shank for engagement of an
impact shank or shank for the implant, which also very greatly facilitates the
positioning.
1o According to a further development, an adjustable stop serves for limiting
the
depth of penetration of an implant into an intervertebral space.
The invention also comprises a novel implant for use as an intervertebral disc
prosthesis in an intervertebral space and/or for the preparation of an
intervertebral space for use of the implant, having a superior and inferior
bearing surface and having at least one anchorage keel each on each bearing
surface, the anchorage keel being held removably or lockably on the implant.
Such an implant would make it possible to avoid the use of a trial implant and
would thus accelerate the operation process. The anchorage keel should be
lockable in the guide slot.
This guide slot may serve for guiding a chisel and is preferably in the form
of a
trapezoidal guide. In addition to the guide slot, a tapped hole for a stop
screw
for stopping a trapezoidal foot of the keel is provided.
In a further embodiment according to the invention, the anchorage keel itself
is
in the form of a chisel, it being possible for the chisel to have passages.
The implant according to the invention is formed for insertion between two
vertebrae at about 45 to the medial plane.
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In a further embodiment according to the invention, the anchorage keel is
fixed
to a rotation plate which is rotatably and lockably mounted in the bearing
surface, the implant having, parallel to the bearing surface, a slot through
which
5 a clamping screw can pass, which clamping screw can be screwed tight in a
tapped hole in the rotation plate.
The novel trial implant with a chisel guided therein serves for the
preparation of
the grooves, the chisel being guided in the superior bearing surface so that,
io when it is subjected to an impact, a groove in the superior vertebra and in
the
inferior bearing surface is guided so that a groove forms in the inferior
vertebra,
the two grooves forming at in each case a right angle to the respective
intervertebral surface.
15 The implant according to the invention and/or the trial implant are
preferably
designed in such a way that the impact shank on its proximal end has a
coupling piece for force-transmitting coupling to the shank, which coupling
piece
has two locks which act separately from one another and have a frictional or
interlocking connection and at least one of which is capable of remote release
2o and the two couplings can each transmit at least either a torque or an
axial
force.
According to the invention, the impact shank of the implant or of the trial
implant
has, at its distal end, an impact head which has impact surfaces on both
sides,
i.e. in the distal direction as well as in the proximal direction. The impact
shank
is preferably provided between its proximal and distal ends with a detachable
and displaceable support rod which can be fixed to the impact shank by means
of a lockable clamping device.
3o According to a further development, the implant and/or trial implant
according to
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the invention has a detachable and adjustable stop, the adjustable stop having
a
captive stopper body on an adjusting screw, and the adjusting screw having a
larger external diameter at its proximal end than that bore in the stopper
body
which it passes through, and the adjusting screw having, at its distal end, an
actuator which likewise has a larger external diameter than the bore. This
adjustable stop is preferably arranged directly adjacent to the shank in order
to
stop excess impact force from the impact shank directly at the shank.
According to a further development, the adjustable stop is arranged directly
io adjacent to the shank and has a bore by means of which it can be guided at
least approximately without play on the shank.
On its proximal stop side, the adjustable stop may have a groove-like recess,
and this recess is supported with its lateral surfaces in the impacted state
at
least approximately without play on the bearing surfaces so that it is guided
in
the normal direction to the bearing surfaces by the implant or trial implant.
A further invention, in particular for use with an implant or a trial implant
for the
preparation of an intervertebral space for use of an intervertebral disc
prosthesis, is a chisel, having a chisel blade and a chisel shank, having an
impact head at its distal end, the chisel shank being connected to a
displaceable guide which can be inserted in particular into at least one of
the
guide slots. This chisel has a guide according to the invention, the guide
being
spring-loaded relative to the chisel shank so that, in the unloaded state, it
is
pushed towards and beyond the proximal end of the chisel blade. In a
particular
development, the guide is connected to a piston which is displaceable in the
interior of the chisel shank under spring load and has a stop for mounting on
a
lateral surface.
so According to the invention, the implants or trial implants, including the
chisel, are
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in the form of set.
The invention also comprises a novel pre-trial implant for the preparation of
an
intervertebral space for insertion of an intervertebral disc prosthesis,
having a
superior and inferior bearing surface, in particular for radiographic and
geographic orientation in the intervertebral space, the pre-trial implant
being
produced substantially from an X-ray-transparent, approximately rectangular or
trapezoidal frame which contains a compound slide which is formed from two
X-ray-visible spindles and carries a carriage body which is firmly connected
to a
1o positioning bar which is oriented at an angle to the two spindles which
corresponds to the approach angle (e), the positioning bar projecting through
the frame.
According to a particular development, the carriage body carries X-ray-visible
markers.
The invention also comprises a novel device for keeping an intervertebral
space
open for a discectomy and/or for the insertion of an implant or trial implant
or
pre-trial implant according to one of the preceding specifications, said
device
2o being formed from two struts which are independent of one another and can
be
selected from a group of leaf-like, different struts, the two struts having a
wedge
shape at the angle of lordosis in their proximal region and optionally being
medially curved at their proximal end.
According to the invention, the struts are toothed in their proximal region at
their
edges facing the vertebrae, and have a coupling device at their distal end for
direct or indirect connection to an attachment frame (e.g. Synframe ,
trademark of Synthes).
In order to facilitate the access to the vertebrae, at least one of the two
struts is
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angled in the medial direction in its distal region. At least one of the two
struts
can be reduced in height between its proximal and its distal region.
According to the invention, the two struts can be connected by means of
connecting pieces at their distal end, and the connecting piece can be
connected to a handle, preferably by means of a detachable coupling, the
handle having guide elements for laterally supporting the struts.
The invention also comprises a novel assembly tool for assembling an
1o intervertebral disc implant having a superior and an inferior implant plate
and an
inlay -in particular according to one of the preceding specifications - with a
baseplate and a base as well as a collet in the base, the collet being formed
for
interlocking with an implant plate, and a batten-like guided sliding element
which has an interlocking receptacle for the inlay is coordinated with the
base,
the two implant plates and inlay being capable of being placed in their
receptacles so that they are correctly positioned relative to one another and
lock
with one another after insertion of the sliding element with inserted implant
plate
and inserted inlay.
2o According to a preferred development, the base and the sliding element are
slideably connected to one another by means of a parallel guide.
The invention also comprises a novel inserter for inserting a trial implant or
an
implant according to one of the preceding specifications, having a hand grip
of
a bar and a retaining mechanism, the retaining mechanism having a locking
part and an implant collet, and the implant collet having a locking lever
which, in
the inserted state, can hold an implant in the implant collet or release it in
a
controlled manner, and the actuation of the locking part and of the locking
lever
being effected by a rod or by an actuating part guided in a rod.
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According to a particular further development of the inserter, a rod carrying
a
hand grip at its distal end, an actuating handle which is connected to the
actuating part in the rod is provided in the region of the hand grip.
A locking lever of this inserter is preferably medially curved at its free
proximal
end in order thus - in the locked state - to secure a trial implant or an
implant
also to prevent loss in the proximal direction.
In order to permit size adaptations for individual use of implants and in
order to
io be able better to design it as set, the implant collet is, according to the
invention, designed in a plurality of parts and comprises a collet which can
be
selected from a group which can be fixed by means of the locking part to a
rod,
the respective collet being formed diametrically oppositely to the distal part
of
the respective trial implant or respective implant. The fixing of the
respective
collet to the locking part is effected by means of at least one guide pin
which is
longitudinally displaceable together with the locking part on the rod.
In a further embodiment, the inserter comprises a device for holding and
inserting a superior implant plate and an inferior implant plate of an
intervertebral implant, said inserter comprising a device by means of which
the
inlay can be introduced by left oblique anterior insertion at about 45 after
insertion of the two implant plates with spreading thereof.
The invention also includes an intervertebral implant in the form of an
intervertebral disc prosthesis having a superior implant plate, an inferior
implant
plate and an inlay having at least one anchorage keel (for anchorage each in a
superior and in an inferior adjacent vertebra) of a spine, the anchorage keel,
in
the installed state, lying in a plane which extends at about 45 to the medial
plane of the spine.
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According to a particular development, this anchorage keel has cockscomb-like
teeth at its free end facing the respective vertebra, the toothed system
having an
inclination which facilitates insertion but prevents removal, by virtue of the
fact
that the flanks of the teeth in the distal direction have a shallower
inclination than
5 the flanks of the teeth in the proximal direction.
This intervertebral implant or implant is coated with a titanium foam or
granular
titanium over the predominant part of its surface so that it can better
integrate
with the bones.
The devices, equipment and instruments are used in a method according to the
invention for the insertion of an intervertebral implant into an
intervertebral space
between a superior and an inferior vertebra, the intervertebral implant
comprising a superior implant plate, an inferior implant plate and an inlay,
and
the intervertebral implant being inserted at about 45 with a left oblique
anterior
approach into at least one prepared groove each in the superior and inferior
vertebra.
According to the invention, in a variant, the intervertebral implant can be
inserted all in one, or first the two implant plates can be inserted at about
45
and then the inlay can be inserted using an instrument according to the
invention
at about 45 .
Preferably, each prepared groove for one keel each of the implant plates in
the
superior and inferior vertebra makes an angle of 90 with the respective
intervertebral surface.
An X-ray observation using the sighting slots and/or the guide slot is
preferably
made during the insertion and positioning of the implant or trial implant.
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In the method for the preparation of an intervertebral space through removal
of
the intervertebral disc and subsequent chiselling of at least one groove each
into the superior and inferior vertebrae, a trial implant is pushed into the
intervertebral space and is held by the vertebrae under the tension of the
muscles.
A trapezoidal guide of a chisel is then inserted into a trapezoidal guide
slot, this
guide slot and the guide holding the chisel at about 900 to the respective
intervertebral surface and at an invariable normal distance. The chisel which
is
1o longitudinally displaceable relative to the guide is then tapped stepwise
into the
respective vertebra up to a stop. Both the insertion of the trial implant and
the
chiselling are effected at about 45 relative to the medial plane.
The method using the devices and instruments according to the invention for
positioning and fixing an intervertebrai implant in the intervertebral space
therefore preferably comprises the following steps:
in a first step, a trial implant adapted to the intervertebral space is
positioned in the cleaned intervertebral space (with or without struts) at a
surgical approach angle e of about 45 ,
in a second step, one groove each is tapped into the superior and inferior
vertebrae, normal to the respective intervertebral surface, using a chisel
guided in the trial implant, and
in a third step, struts are used laterally with respect to the trial implant,
in a fourth step, the trial implant is removed
and in a fifth step, the implant is inserted either all in one completely with
both implant plates and the inlay using an inserter according to the
invention,
or, using another inserter, first upper and lower part of the implant and then
the inlay are inserted.
The positioning of the trial implant in the intervertebral space is effected
with
the aid of a shank mounted on the trial implant, under radiographic
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monitoring, using sighting slots in the trial implant and optionally by
impacts
on impact hollows at the periphery.
By turning the adjusting screw of the adjustable stop using a screwdriver, a
trial implant inserted a track too far can also be pulled back.
The trunk of the trial implant is, if required, fixed by means of the impact
shank
on a frame (Synframe , trademark of Synthes) or held by a person.
In an alternative method according to the invention, for increasing the
accuracy
lo of fit, the chisel guided in the trial implant is left in the superior or
inferior groove
after the chiselling, and the opposite groove is then chiselled using a
further
chisel.
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List of reference numerals/parts of the invention
I Superior vertebra
2 Inferior vertebra
3 Groove in superior vertebra
4 Groove in inferior vertebra
5 Upper/superior implant plate
6 Inlay, preferably of polyethylene
7 Lower/inferior implant plate
The plates 5 and 7 are named as superior and inferior, but they can
also be formed or installed vice versa. Thus, the inlay can also be
fixed, for example, on the superior plate.
8 Impact shank for trial implant, mounted on the guide shank 22 if
required.
9 Trial implant
10 Chisel
11 Upper/superior guide slot for chisel 10 or guide slot for keel 54a'
12 Lower/inferior guide slot for chisel 10 or guide slot for keel 54b'
13 Inserter for insertion of 45 implant (all in one)
14 45 implant (all in one)
15 45 implant, divided embodiment
16 Inserter for insertion at 45 , first insertion of upper and lower part and
subsequently insertion of inlay
17 Adjustable stop
18 Assembly tool, preferred for assembly since the implant can be
assembled before despatch and packing or at the operating table itself
before surgery. This makes it easier for the operating theatre staff to
produce, according to the invention, the correct combination in each
case from a selection of plates and inlays.
19 Collet (receptacle for implant)
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20 Strut ieft
21 Strut right
22 Trial implant shank is a handle and guide for impact shank 8
23 a, b Parallel guidance of 18, e.g. by means of guide pins, the implant is
inserted over head to ensure that the bone ingrowth layer on the surface
of the implant plate is not damaged during insertion of the inlay, which
might weaken the connection to the bone.
24 a, b Impact hollows, at least one on the trial implant
25 Thread for adjustable stop
26 a,b Lateral sighting slots
27a,b Anterior-posterior (AP) sighting slots
28 Chisel shank
29 Impact head
30 Chisel blade
31 Fit-in guidance for the guide slots 11 and 12
32 Piston
33 Spring
34 Rinse slot
35 Bearing pin
36 Bearing pin axle
37 Distance piece
38 Locking lever
39 Joint pin
40 Actuating bar
41 Actuating handle
42 Rod
43 Locking part
44 a,b Guide pin
45 Hand grip
46 Insert pin for superior plate
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47 a,b Insert pin for inferior plate
48 Spring
49 Support rod for attachment on Synframe or on another support device
50 Clamping device
5 51 Impact bar
52 Mallet with notch which fits into the shank of the chisel
53 Screwdriver
54a Upper anchorage keel of the implant
54b Lower anchorage keel of the implant
10 55 Double arrow
56 Slot
57 Clamping screw
58 Tapped hole
59 Rotation plate
15 60a,b Upper and lower keel socket
61 Tapped hole
62 Intervertebral space
63 Superior bearing surface of the trial implant
64 Inferior bearing surface of the trial implant
20 65 Lateral surface
66 Stop screw
67 Coupling piece between shank 22 and impact shank 8
68 Impact head
69 Stopper body
25 70 Adjusting screw
71 Actuator
72 Bore
73 Superior bearing surface of the implant
74 Inferior bearing surface of the implant
75 Stopper
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76 Frame
77 a,b X-ray-visible spindles
78 Carriage body
79 Pre-trial implant
80 Positioning bar
81 Proximal area
82 Edges of struts
83 Coupling device of struts
84 Attachment frame
85 Distal area of the struts
86 Distal end of the struts
87 Connecting piece
88 Handle connected to the connecting piece
89 Coupling
90 Guide element for lateral support
91 Baseplate
92 Base
93a Collet for implant plate
93b Collet for the inlay
94 Sliding element
95 Proximal end of the locking lever 38
96a,b X-ray-visible markers of the carriage body 78
97 Actuating element
98 Proximal end
99 Connecting handle to the struts
100 Strut left
101 Strut right
102 Handle
103 Lock
104 Impact plate
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105 Recesses for screwdrivers
106 Impact pipe
107a,b Guide rail for struts
108 Support rod
109 Lock
110 Module device
111 a,b Cockscomb-like end of the keels which faces the vertebra
112a,b Teeth of the keels
113 Proximal end
x.... Distance from the end region of the grooves to the spinal canal
a...Angle of lordosis = angle of the bearing surface of the trial implant =
angle of the implant 14, 15
f3...Angle between the anchorage keels
?...Angle between sighting slot and guide slot or between the AP line and
the anchorage keels 54a,b
d ... Complementary angle to ? between sighting slot and guide slot
e.... Surgical approach angle, the angle between AP and the approach of
the surgeon to the vertebra
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DESCRIPTION OF THE DRAWINGS
Fig. 1: A chisel 10 having a chisel blade 30 (monochisel), a diametrically
opposite guide part 31 and a shank 28 with an impact head 29 and a stopper
75;
Fig. 2: A mallet 52 having a hammer shape according to the invention and a
notch which fits into the shank 28 of the monochisel 10;
lo Fig. 3: A handle for the trial implant 8. The handle 49 is held either by
an
operating theatre nurse or a frame (e.g. Synframe , trademark of Synthes)
while the trial implant is being positioned by impact on the impact head;
Fig. 4: Trial implant 9 having shaft 22 and an adjustable stop 17 as an
1s adjustable stopper, superior bearing surface 63;
Fig. 5: An inserter 13 having a collet 19, actuating handle 41 and hand grip
45;
Fig. 6: An impact bar 51 for tapping the trial implant 9 into the
intervertebral
space 62;
Fig. 7: A screwdriver 53 for use with a stopper according to the invention;
Fig. 8: Struts 20, 21;
Fig. 9: An assembly tool 18 for assembly of an implant on site;
Fig. 10: An implant 5, 6, 7 with superior 63 and inferior 64 bearing surface,
view
in the direction of an anchorage keel;
3o Fig. 11: The implant 5, 6, 7 with superior 63 and inferior 64 bearing
surface,
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anchorage keel 54a; view in the anterior-posterior (AP) direction;
Fig. 12: The implant 5, 6, 7 with superior 63 and inferior 64 bearing surface,
45
view;
Fig. 13: The implant 5, 6, 7 with superior 63 and inferior 64 bearing surface,
side view;
Fig. 14: The impiant 5, 6, 7 with superior 63 and inferior 64 bearing surface,
1o oblique view with the AP and lateral planes;
Fig. 15: Overview of different-size implants M (medium) and L (large), with PE
inlays 6 in the sizes 10 mm, 12 mm, 14 mm, and superior plates 5 with the
angles of lordosis 0 , 3 , 6 , and the inferior plate 7 with 0 and 3 and the
inlay
6;
Fig. 16: Overview of the choice of implant: during the operation, the surgeon
chooses implants of size M or L according to the bearing surface of the
vertebra. The inlays 6 with the sizes 10 mm, 12 mm or 14 mm are mounted
2o between the superior plate 5 and the inferior plate 7. This results,
through
pairing of a superior plate 5 with an inferior plate 7, in implants having an
angle
of lordosis of 3 , 6 , 9 or 12 . 12 is an exception and is reserved for the
specially trained surgeon for special cases;
Fig. 17: AP view of an implant variant according to the invention, having
superior plate 5', inferior plate 7' and an inlay 6, with a superior bearing
surface
73, an inferior bearing surface 74 with anchorage keel 54b, a superior
rotatable
anchorage keel 54a. The anchorage keel 54a is fixed to a rotation plate 59
(cf.
Fig. 18). Through a slot 56, the rotation plate 59 can be fixed to the plate
5' by
means of a clamping screw 57 through a tapped hole 58;
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Fig. 18: An oblique view of the implant 5', 6, 7' having superior plate 5',
inferior
plate 7' and an inlay 6, with a superior bearing surface 73, an inferior
bearing
surface 74, a superior rotatable anchorage keel 54a; the double arrow 55
5 indicates the direction of rotation. The anchorage keel 54a is fixed to a
rotation
plate 59. Through a slot 56, the rotation plate can be fixed to the superior
plate
5' by means of a clamping screw 57 through a tapped hole 58;
Fig. 19: A further variant having mobile keels 54a' and 54b'. The keels 54a'
and
1o 54b' with the keel sockets 60a and 60b rest in a guide slot 11' and are
fixed
through a tapped hole 61 a by means of a stop screw 66. This variant can be
presented either only above or above and below or only below;
Fig. 20: A trial implant 9 having shaft 22, superior and inferior guide slot
11, 12,
15 with sighting slots 27a,b;
Fig. 21: A trial implant 9 having shaft 22, superior and inferior guide slot
11, 12
(cf. Fig. 22), with sighting slots 27a,b with adjustable stop 17;
Fig. 22: A trial implant 9 having shaft 22, superior and inferior guide slot
11, 12,
20 with sighting slots 27a,b, with impact hollows 24a,b, with thread 25 for
the
adjustable stop 17, with sighting slots 26a,b. The sighting slots may also be
filled with a X-ray-transparent material;
Fig. 23: A trial implant 9 having shaft 22, superior and inferior bearing
surface
25 63, 64 with sighting slots 26a,b.
Fig. 24: A trial implant 9 having shaft 22, superior and inferior guide slot
11, 12
(cf. Fig. 26), with sighting slots 27a,b (cf. Fig. 21) with impact hollows
24a,b,
with thread 25 for the adjustable stop, with sighting slots 26a,b.
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Fig. 25: A trial implant 9 having shaft 22, superior and inferior bearing
surface
63, 64, superior and inferior guide slot 11, 12, with sighting slots 27a,b
with
impact hoilows 24a,b, with thread 25 for the adjustable stop, with sighting
slots
26a,b.
Fig. 26: A trial implant 9 having shaft 22, superior and inferior bearing
surface
63, 64, superior and inferior guide slot 11, 12, with sighting slots 27a,b
(underside) with impact hollows 24a,b, with thread for the adjustable stop 17,
with sighting slots 26a,b (underside), with adjustable stop 17, having a
mobility
1o of about 9 mm.
Fig. 27: A chisel 10 in the starting position with chisel blade 20, fit-in
guidance
31, with piston 32, spring 33 and rinse slot 34;
Fig. 28: A chisel 10 in the starting position with chisel blade 30, fit-in
guidance
31 with stopper 75, with piston 32, with spring 33 and with rinse slot 34;
Fig. 29: A chisel 10 in the starting position with chisel blade 30, fit-in
guidance
31 with stopper 75, with piston 32, with spring 33;
Fig. 30: Plan view of a chisel 10 in the impact position with chisel blade 30,
fit-in
guidance 31, with piston 32, spring 33 and rinse slot 34;
Fig. 31: Side view of a chisel 10;
Fig. 32: Oblique view of a chisel 10;
Fig. 33: Inserter 13 with actuating handle 41, with hand grip 45, with rod 42,
with
locking part 43 and with collet 19;
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Fig. 34: Inserter 13 with locking part 43 and guide pins 44a,b with bearing
pin
35 in the bearing pin axle 36, with lever 38 for holding the implant, with
insert pin
for superior plate 46 with joint pin 39 and actuating bar 40, and a set of
collets
19a-c, with the preferred heights 10, 12, 14 mm, which are interlocked with
the
implant;
Fig. 35: Inserter 13 within locking part 43 and with collet 19, with bearing
pin 35,
insert pins for inferior plate 47a,b and insert pin for superior plate 46. An
individual collet 19a-c (cf. Fig. 34) is coordinated with each implant plate
5, 7
1 o with inlay 6 (cf. Fig. 10);
Fig. 36: Inserter 13 with locking part 43, spring 48, with lever 38 for
holding the
implant, actuating bar 40, with insert pin 46 for the superior implant plate
5, with
insert pins 47a,b for the inferior implant plate 7 (not shown);
Fig. 37: Inserter 13 with rod 42 with locking part 43 and with collet 19, with
bearing pin 35 in the bearing pin axle 36, with lever 38 for holding the
implant,
with joint pin 39 and actuating bar 40 with insert pin 46 for the superior
implant
plate 5, with insert pins 47a,b for the inferior implant plate 7 (not shown) ;
Fig. 38: Inserter 13 with actuating handle 41, with hand grip 45, with rod 42;
Fig. 39: Inserter 13 in the unlocked position, rod 42 with locking part 43 and
with
collet 19, with bearing pin 35, distance piece 37, with lever 38 for holding
the
implant, with joint pin 39 and actuating bar 40, and a collet 19 with inserted
superior implant plate 5, with insert pins 47a,b for the inferior implant
plate 7 (cf.
Fig. 41);
Fig. 40: Inserter 13 in the locked position, rod 42 with locking part 43 and
with
collet 19, with bearing pin 35, distance piece 37, with lever 38 for holding
the
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implant, with joint pin 39 and actuating bar 40 and a collet 19, with inserted
superior implant plate 5, with insert pins 47a,b for the inferior implant
plate 7
(not shown);
Fig. 41: Inserter 13 with locking part 43 and with collet 19a, with bearing
pin 35,
distance piece 37, and inserted implant 5, 6, 7;
Fig. 42: Handle 8 with impact head 68 for the trial implant with support rod
49
for attachment on Synframe or on another support device, with a clamping
1 o device 50;
Fig. 43: Handle 8 for the trial implant with support rod 49 for attachment on
Synframe or on another support device, with a clamping device 50 in the end
position, before the impact head 68;
Fig. 44: Handle 8 with impact head 68 and coupling piece 67 for the trial
implant with support rod 49 for attachment on Synframe or on another support
device, with a clamping device 50;
2o Fig. 45: Clamping device 50 with handle 8 and support rod 49;
Fig. 46: Trial implant 9 inserted into the intervertebral space 62 between the
superior vertebra 1 and the inferior vertebra 2 with an adjustable stop 17 and
a
shank 22. The trial implant can be brought into the correct position with the
impact bar 51 by tapping into the impact hollows 24a,b. The adjustable stop 17
prevents the trial implant 9 from being pushed too deeply into the
intervertebral
space 62;
Fig. 47: Trial implant 9 inserted into the intervertebral space 62 between the
superior vertebra I and the inferior vertebra 2 with a shank 22, and with
impact
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hollows 24a, b and the thread 25 for the adjustable stop 17 (cf. Fig. 46);
Fig. 48: Trial implant 9 inserted into the intervertebral space 62 between the
superior vertebra I and the inferior vertebra 2 with a shank 22, and with
impact
hollows 24a and adjustable stop 17 and with the sighting slots 27a,b, viewed
from the anterior-posterior direction;
Fig. 49: Trial implant 9 inserted into the intervertebral space 62 between the
superior vertebra 1 and the inferior vertebra 2 with a shank 22, and with
1o adjustable stop 17 and with the sighting slots 26a,b, viewed from the
lateral
direction;
Fig. 50: Trial implant 9 inserted into the intervertebral space 62 between the
superior vertebra I and the inferior vertebra 2 with a shank 22 and with
impact
hollows 24a,b and adjustable stop 17 and with the screwdriver 53 for adjusting
the depth of penetration of the trial implant with the adjustable stop 17,
with
stopper body 69, adjusting screw 17 and actuator 71;
Fig. 51: Trial implant 9 with adjustable stop 17 and shank 22, inserted
between
2o a superior vertebra 1 and an inferior vertebra 2, and chisel 10 having fit-
in
guidance 31 and a chisel blade 30, fixed to a chisel shank 28;
Fig. 52: Trial implant 9 with adjustable stop 17, inserted between a superior
vertebra 1 and an inferior vertebra 2, and chisel 10 having a fit-in guidance
31
and a chisel blade 30, attached to a chisel shank 28 with impact head 29;
Fig. 53: Trial implant 9 with adjustable stop 17, inserted between a superior
vertebra I and inferior vertebra 2, and chisel 10, attached to a chisel shank
28,
with retracted chisel blade 30;
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Fig. 54: Plan view of a trial implant 9 having sighting slots 26a and 27a,
with
adjustable stop 17, inserted between a superior vertebra 1 and an inferior
vertebra 2, and chisel 10 with a fit-in guidance 31 and a chisel blade 30
attached to a chisel shank 28, with retracted chisel blade 30 before
penetration
5 into the guide slot 11;
Fig. 55: Plan view of a trial implant 9 having sighting slots 26a and 27a,
with
adjustable stop 17, inserted between a superior vertebra I and an inferior
vertebra 2, and chisel 10 with a fit-in guidance 31 and a chisel blade 30
1o attached to a chisel shank 28, with retracted chisel blade 30 before
penetration
into the guide slot 11;
Fig. 56: Trial implant 9 having adjustable stop 17, inserted between a
superior
vertebra I and an inferior vertebra 2, and chisel 10, attached to a chisel
shank
15 28, with tapped-in chisel blade 30;
Fig. 57: Plan view of a trial implant 9 with sighting slots 26a and 27a, with
adjustable stop 17, inserted between a superior vertebra 1 and an inferior
vertebra 2, and chisel 10 and a chisel blade 30, attached to a chisel shank
28,
20 with tapped-in chisel blade 30 in the guide slot 11;
Fig. 58: Bottom view of a trial implant 9, with adjustable stop 17, inserted
between a superior vertebra 1 and an inferior vertebra 2, and chisel 10 with
tapped-in chisel blade 30;
25 Fig. 59: Side view of groove 3 in the superior vertebra I and of groove 4
in the
inferior vertebra 2 after chiselling; with inserted trial implant 9 with
adjustable
stop 17;
Fig. 60: Front view of groove 3 in the superior vertebra 1 and of groove 4 in
the
30 inferior vertebra 2 after chiselling, with inserted trial implant 9 with
adjustable
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stop 17;
Fig. 61: Oblique view of a superior vertebra 1 and of an inferior vertebra 2
with
chiselled groove 3, with inserted trial implant 9 with adjustable stop 17 and
shank 22, and with inserted left 20 and right 21 struts;
Fig. 62: Plan view of an inferior vertebra 2, with inserted trial implant 9
with
adjustable stop 17 and shank 22, and with inserted left 20 and right 21
struts.
The trial implant 9 is at distance x from the end region of the grooves to the
io spinal canal. The struts 20 and 21 are inserted at the surgical approach
angle e
to the left and right of trial implant 9. The right strut 21 is angled at
about 20 in
the middle part in order to permit a better view;
Fig. 63a-e: Implant assembly tool 18 for assembling the implant with the inlay
6
(Fig. 63c,d) and the inferior plate 7 (Fig. 63c-e); with baseplate 91, base 92
and
collet for the implant plate with the inlay 93 (Fig. 63a,b).
Fig. 64: Upper vertebra I and inferior vertebra 2 with the chiselled grooves 3
and 4, with inserted struts 20 and 21, and with the inserter 13 for insertion
of the
2o 45 implant 5, 6, 7 all in one (both superior plate 5 and inferior plate 7
with
inserted inlay 6 simultaneously);
Fig. 65: Inserter 13 with the collet 19 and the 45 implant 5, 6,7 (all in
one);
Fig. 66: Plan view of the inferior vertebra 2 with the chiselled groove 4 at
the
distance x from the spinal canal, with inserted struts 20 and 21, and with the
inserter 13 for the insertion of the 45 implant 5, 6, 7 all in one;
Fig. 67: Oblique view of a superior vertebra 1 and inferior vertebra 2 with
the
groove 3 in the inserted inserter 13 between the struts 20 and 21 in the
intervertebral space 62;
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Fig. 68: Front view of an inserted implant 5, 6, 7 between the upper vertebra
I
and the inferior vertebra 2; the keel of the superior plate 5 is guided in the
groove 3, and the keel of the inferior plate 7 is guided in the groove 4;
Fig. 69: Side view of an inserted implant 5, 6, 7 between the superior
vertebra 1
and the inferior vertebra 2; the keel of the superior plate 5 is guided in the
groove 3, and the keel of the inferior plate 7 is guided in the groove 4;
1o Fig. 70: Oblique view of a pre-trial implant 79 having a frame 76 and a
positioning bar 80, and a superior bearing surface 63" and an inferior bearing
surface 64";
Fig. 71 a: Side view of the short side of a pre-trial implant 79 having a
frame 76
and a positioning bar 80, with a carriage body 78, and a superior bearing
surface 63" and an inferior bearing surface 64";
Fig. 71 b: Side view of the longer side of the pre-trial implant 79 having a
frame
76 and a positioning bar 80, with a carriage body 78, and a superior bearing
surface 63" and an inferior bearing surface 64";
Fig. 72a: Side view of Fig. 71 a as an X-ray image with the X-ray-visible
spindles 77a and 77b;
Fig. 72b: Side view of Fig. 71 b as an X-ray image with the X-ray-visible
spindles 77a and 77b;
Fig. 73: Oblique view of a pre-trial implant 79 having a frame 76 and a
positioning bar 80, and a superior bearing surface 63" and an inferior bearing
surface 64" and with the X-ray-visible spindles 77a and 77b;
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Fig. 74: Oblique view of a pre-trial implant 79 having a frame 76 and a
positioning bar 80;
Fig. 75: Pre-trial implant 79 having a frame 76 and a positioning bar 80 on an
inferior vertebra 2;
Fig. 76a: Sectional diagram of a pre-trial implant 79 having a frame 76 and a
positioning bar 80 and a carriage body 78 on an inferior vertebra 2,
surrounded
io by tissue;
Fig. 77a: Side view of a pre-trial implant 79 having a frame 76 and a
positioning
bar 80 and a carriage body 78 between a superior vertebra I and an inferior
vertebra 2;
Fig. 77b: Front view of a pre-trial implant 79 having a frame 76 and a
positioning bar 80 and a carriage body 78 between a superior vertebra I and
an inferior vertebra 2;
2o Fig. 78a: Side view of a pre-trial implant 79 as an X-ray representation
with the
X-ray-visible spindles 77a and 77b between a superior vertebra 1 and an
inferior vertebra 2, the mid-line (dashed) not yet having been reached;
Fig. 78b: Side view of a pre-trial implant 79 as an X-ray representation with
the
X-ray-visible spindles 77a and 77b between a superior vertebra 1 and an
inferior vertebra 2, with which the spindle 77a is aligned exactly with the
mid-line
(dashed);
Fig. 79: Side view of a strut 20 (left) having a proximal area 81, a blade
having
edges 82, distal area 85, a coupling device 83 and a coupling 89. The strut 20
is connected by means of a connecting piece 87 to a handle 88 which is
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attached at the distal end 86 to an attachment frame 84. The handle 88 can
also
be attached to an attachment frame 84 which is held by a guide element 19 for
lateral support.
Fig. 80: Left diagram: Strut 20, distal area 85 is separated from a coupling
device 83,
right diagram: Strut 20 is connected at the distal end to the coupling device
83;
Fig. 81 a,b,c: Strut 20 in 3 different sizes with a proximal area 81, a blade
having
1o edges 82 and a distal end 86;
Fig. 82a: Angled strut 21 with a proximal area 81, a blade having edges 82,
distal area 85 and a distal end 86, the two struts (20, 21) being wedge-shaped
at the angle of lordosis in their proximal area 81 and being medially curved,
e.g.
at about 20 at their proximal end;
Fig. 82b: Straight strut 20 with a proximal area 81, a blade having edges 82,
distal area 85 and a distal end 86, the two struts (20, 21) being wedge-shaped
at the angle of lordosis in their proximal area 81;
Fig. 83: Struts 100, 101, connected by a handle 99, guided in rails 107a,b.
With
the handle 102, the handle is connected to the support rod 108 by a lock 103
by
means of lock 109. By tapping on the impact head 104 having recesses 105a,b
for screwdriver 53 and impact pipe 106, the struts 100, 101 which are guided
by the rails 107a,b can slide in the intervertebral space. The struts have a
proximal area 81 having edges 82;
Fig. 84: According to Fig. 83 but with a trial implant arranged underneath.
The trial implant 9 can be pushed into the impact pipe 106 by means of the
shank 22. An adjustable stop 17 is present on the trial implant;
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Fig. 85: According to Fig. 83 or Fig. 84. The trial impiant 9 is pushed into
the
impact pipe 106 by means of the shank 22.
5 Fig. 86a: Side view of a strut 100, 101, connected by a handle 99, guided in
rails 107a,b. With the handle 102, the handle 99 is connected to the support
rod
108 via a lock 103 by means of lock 109. By tapping on the impact head 104,
the struts 100, 101 which are guided by the rails 107a,b can slide in the
intervertebral space 62 (not shown). The struts have a proximal area 81 having
1 o edges 82.
Fig. 86b: Plan view of a strut 100, 101, connected by a handle 99, with lock
103.
An adjustable stop 17 is present on the trial implant 9;
15 Fig. 86c: Front view of a strut 100, 101, guided in rails 107a,b, and
handle 102.
By tapping on the impact head 104, struts 100, 101 which are guided by the
raiis 107a,b can slide in the intervertebral space 62 (not shown). The trial
implant 9 is pushed into the impact pipe 106. An adjustable stop 17 is present
on the trial implant 9;
Fig. 87: Detailed view of the guide rails 107a,b with the impact pipe 106;
Fig. 88: Detailed view of the impact head 104 with the recesses 105a,b;
Fig. 89: Detailed view of the lock 103 with locking peg 109, the handle 102
and
the support rod 108;
Fig. 90a: Side view of the struts 100, 101 connected to the handie 99, with
proximal area 81 and edges 82;
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Fig. 90b: Oblique rear view of the struts 100, 101 connected to the handle 99,
with proximal area 81 and edges 82;
Fig. 90c: Oblique front view of the struts 100, 101 connected to the handle
99,
with proximal area 81 and edges 82;
Fig. 91: Holding and impact device 110 (for the struts 100, 101) with handle
102, support rod 108, lock 103, locking peg 109, impact head 104 with
recesses 105a,b, impact pipe 106 and guides 107a,b;
Fig. 92a: Plan view of the holding and impact device 110 (for the struts 100,
101), with handle 102, lock 103 and impact head 104.
Fig. 92b: Side view of the holding and impact device 110 (for the struts 100,
101), with handle 102, lock 103, locking peg 109, support rod 108, impact head
104, impact pipe 106 and guide 107a;
Fig. 92c: Front view of the holding and impact device 110 (for the struts 100,
101), with handle 102, lock 103, impact head 104, impact pipe 106 and guides
107a,b;
Fig. 93: Plan view of the holding and impact device 110 for the struts 100,
101,
with handle 102, lock 103, support rod 108, impact head 104 with recesses
105a,b and struts 100, 101, connected to the handle 99;
Fig. 94: Front view of the holding and impact device 110 for the struts 100,
101,
with handle 102, impact head 104, impact pipe 106 with inserted struts 100,
101 connected to the handle 99, with proximal area 81, with edges 82;
so Fig. 95: Impact pipe 106 with guide 107a,b and inserted struts 100, 101
with
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proximal area 81 and edges 82.
Fig. 96: Cross-section through an adjustable stop 17 inserted into a trial
implant
9, with stopper body 69, adjusting screw 70, actuator 71 and bore 72, and
Fig. 97: An inserter 16 with module device 110 for subsequent insertion of an
inlay 6 between the upper implant plate 5 and lower implant plate 7.
lo The figures are described overall. Identical reference numerals denote
identical
components. Identical reference numerals having different indices denote
functionally similar components.
BEST MODE OF EMBODIMENTS OF PREFERRED PROCEDURES OR
METHODS FOR USING THE INVENTION
A trial implant 9 (Fig. 20-23) having a superior and inferior bearing surface
63,
2o 64 and having one guide slot 11, 12 each in the superior and inferior
bearing
surface 63, 64 serves for the preparation of an intervertebral space 62 for
insertion of an intervertebral disc prosthesis according to the invention. At
least
one of the guide slots 11, 12 is formed in such a way that an insertable or
inserted guide 31 can be held or is held nondisplaceably in two directions in
space - in particular parallel and normal to the respective bearing surface.
The guide slots 11, 12 serve for guiding a chisel 10 (Fig. 1) in the trial
implant 9.
According to the invention, the chisel is in the form of a monochisel 10 which
is
connected to a guide 31 which is displaceable relative to it and is formed
3o diametrically opposite to the respective guide slot 11, 12. The two guide
slots
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11, 12 are at an angle 9 relative to one another in different positions in
space.
At least one of the slots 26a, 26b, 27a, 27b in the trial implant 9 (Fig. 20-
23)
serves as a sighting slot. It is formed in such a way that, when a trial
implant 9 is
inserted into an intervertebral space 62, it enables the position thereof to
be
detected relative to the vertebrae 1, 2 by means of X-rays.
The sighting siots of the trial implant 9 (Fig. 20-23), 26a, 26b, 27a, 27b,
are at
an angle ? or at a complementary angle d to the respective guide slot 11, 12.
1o The surgical approach angle e (Fig. 62, 76) corresponds to the direction of
insertion of the implant into the intervertebral space 62 for the implantation
of
the intervertebral disc prosthesis.
The two sighting slots 26a, 26b, 27a, 27b per bearing surface 63, 64 in the
trial
implant 9 (Fig. 20-23) are preferably at a right angle to one another.
The trial implant 9 consists of X-ray-opaque or X-ray-visible material.
The sighting slots 26a, 26b, 27a, 27b in the trial implant 9 (Fig. 20-23) can
be
filled with X-ray-transparent material, e.g. plastic, or the trial implant 9
may be
plastic-coated, e.g. of polyethylene.
Instead of the sighting slots 26a, 26b, 27a, 27b in the trial implant 9 of X-
ray-
transparent material, X-ray-visible inlays may also be provided or the guide
slots 11, 12 may be X-ray-visible.
In the trial implant 9 for the preparation of an intervertebral space 62 (Fig.
46,
47) for insertion of an intervertebral disc prosthesis, having a superior and
inferior bearing surface 63, 64 and having a lateral surface 65 (Fig. 22, 23),
at
least one impact hollow 24a, 24b for the engagement of an impact bar 51 is
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provided on the lateral surface 65.
The trial implant 9 has a guide shank 22 for engagement of an impact shank or
handle 8, and is equipped with an adjustable stop 17 (Fig. 21, 96) which
limits
the depth of insertion of the trial implant 9 into the intervertebral space
62.
For use as an intervertebral disc prosthesis in a prepared intervertebral
space
62, a further implant 5', 6, 7' according to the invention is provided (Fig.
17, 18,
19) having a superior and inferior bearing surface 73, 74 and having at least
1o one guide slot 11, 12 each in the superior and inferior bearing surface 63,
64
(Fig. 10-14), at least one of the guide slots 11, 12 being formed in such a
way
that an insertable or inserted guide 31 can be held or is held nondisplaceably
in
two directions in space- in particular parallel and normal to the respective
bearing surface.
In this implant 5', 6, 7', the guide slot 11, 12 (Fig. 19) serves for guiding
a chisel
10 (Fig. 1). The chisel is in the form of a monochisel 10 and is connected to
a
guide 31 which is displaceable relative to it and is formed diametrically
opposite to the respective guide slot 11, 12. The two guide slots 11, 12 of
the
implant 5', 6, 7' are at an angle f3 relative to one another in different
positions in
space (Fig. 12).
The implant 5', 6, 7' is intended for use as an intervertebral disc prosthesis
in an
intervertebral space 62 (Fig. 64) and for the preparation of the
intervertebral
space 62, having a superior and inferior bearing surface 63, 64 (Fig. 12) and
having at least one slot 26a, 26b, 27a, 27b each in the superior and inferior
bearing surface 63, 64, at least one of the slots being in the form of a
sighting
slot so that, when an implant 5', 6, 7' is inserted into an intervertebral
space 62
(Fig. 18), it enables the position thereof to be detected relative to the
vertebrae
1, 2 by means of X-rays.
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In the case of implant 5', 6, 7', the sighting slots 26a, 26b, 27a, 27b are at
an
angle ? or at a complementary angle d to the respective guide slot 11, 12,
which
corresponds to the surgical approach angle e or the direction of insertion of
the
5 implant 5', 6, 7' into the intervertebral space 62 for the implantation of
the
intervertebral disc prosthesis. Two sighting slots 26a, 26b, 27a, 27b are
provided per bearing surface 62, 63 and are at a right angle to one another.
The implant 5, 6', 7' (Fig. 18) consists partly, in various combinations, of X-
ray-
io opaque or X-ray-visible and of X-ray-transparent or X-ray-invisible
material.
Except for the inlay 6, all parts may comprise metal or plastic; instead of
the
sighting slots 26a, 26b, 27a, 27b, for example, it is also possible to provide
X-
ray-opaque or X-ray-visible inlays, or the guide slots 11, 12 may be X-ray-
visible.
At least one impact hollow 24a, 24b for engagement of an impact bar 51 is
provided on the lateral surface 65 of the implant 5', 6, 7'.
The implant 5', 6, 7' (Fig. 18) has a removable guide shank 22 for engagement
of an impact shank or handle which is equipped with an adjustable and
removable stop 17 which limits the insertion of the implant 5', 6, 7' into the
intervertebral space 62.
The implant 5', 6, 7' (Fig. 18) for insertion as an intervertebral disc
prosthesis
into an intervertebral space 62 and/or for the preparation of an
intervertebral
space 62 for insertion of the implant 5', 6, 7' having a superior and inferior
bearing surface 63', 64' and having at least one anchorage keel 54a', 54b'
each
on each bearing surface 63', 64', has anchorage keels 54a', 54b' which are
removably or lockably held on the implant 5', 6, 7.
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The guide slot 11, 12 in the implant 5', 6, 7' (Fig. 18) or trial implant 9
is,
according to the invention, in the form of a trapezoidal guide (Fig. 19).
In addition to the guide slot 11, 12 in the implant 5', 6, 7', a tapped hole
(Fig. 19)
61 a, 61 b for a stop screw 66 for stopping a trapezoidal socket 60a, 60b of
the
keel 54a', 54b' is provided;
The anchorage keel 54a, 54b, 54a', 54b' in the implant 5', 6, 7' (Fig. 19) may
also be in the form of a chisel, it being possible for the chisel 10 to have
1o passages.
The anchorage keel 54 of the implant 5', 6, 7' (Fig. 18) may be attached to a
rotation plate 59 which is rotatably and lockably mounted in the bearing
surface
63'.
A slot 56 through which it is possible to pass a clamping screw 57 which can
be
tightened in a tapped hole 58 in the rotation plate 59 is provided parallel to
the
bearing surface 63' of the implant 5', 6, 7' (Fig. 18).
With the trial implant 9 and the chisel 10 guided therein, a groove 3 can be
chiselled in the superior vertebra 1 and a groove 4 in the inferior vertebra 2
at
right angles to the respective intervertebral surface (Fig. 53-58).
The impact shank 8 of the implant 5, 6, 7 or trial implant 9 has, at its
proximal
end, a coupling piece 67 for coupling to the shank 22 with force transmission.
The impact shank 8 (Fig. 44) of the implant 5, 6, 7 or trial implant 9 may
have, at
its distal end, an impact head 68 which has impact surfaces on both sides,
i.e.
in the distal direction as well as in the proximal direction. The impact shank
8
3o has, between its proximal and distal ends, a detachable and displaceable
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support rod 49 which can be fixed by means of a lockable clamping device 50
to the impact shank 8.
A detachable and adjustable stop 17 (Fig. 96) is provided for limiting the
penetration of the implant 5, 6, 7 or trial implant 9, the adjustable stop 17
having
a captive stopper body 69 (Fig. 50, 96) on an adjusting screw 70, and the
adjusting screw 70 having a larger external diameter at its proximal end than
that bore 72 in the stopper body 69 through which it passes, and the adjusting
screw 70 having, at its distal end, an actuator 71 (Fig. 50, 96) which
likewise
1 o has a larger external diameter than the bore 72. The adjustable stop 17 is
arranged directly adjacent to the shank 22 in order to stop excessive impact
force from the impact shank 8 directly at the shank 22.
The chisel 10 (Fig. 1) is provided in particular for use with an implant 5',
6, 7'
(Fig. 18) or a trial implant 9 for the preparation of an intervertebral space
62 for
insertion of an intervertebral disc prosthesis. Said chisel has a chisel blade
30
(Fig. 52) and a chisel shank 28 with an impact head 29 on the distal end
thereof, the chisel shank 28 being connected to a displaceable guide 31 which
can be inserted in particular into at least one of the guide slots 11, 12
(Fig. 55).
The guide 31 of the chisel 10 (Fig. 27-29) is spring-loaded against the chisel
shank 28 so that, in the unloaded state, it is displaced towards and beyond
the
proximal end of the chisel blade 30. The guide 31 is connected to a piston 32
which is displaceable under spring load in the interior of the chisel shank 28
and
has a stopper 75 for mounting on the lateral surface 65 (Fig. 55, 58).
The implant 5', 6, 7' (Fig. 18) or trial implant 9 (Fig. 20-23) is provided as
a set
comprising a chisel 10 and the associated tools, such as, for example, mallet
52 (Fig. 2) and impact bar 51 (Fig. 6) and screwdriver 53 (Fig. 7).
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According to the invention, a pre-trial implant 79 (Fig. 70-73) for the
preparation
of an intervertebral space 62 is also used if required. The pre-trial implant
79 is
substantially produced from a X-ray-transparent, approximately rectangular or
trapezoidal frame 76 which contains a compound slide formed from two X-ray-
visible spindles 77a, 77b. The carriage body 78 is firmly connected to a
positioning bar 80 and is oriented at an angle to one of the two spindles 77a
which corresponds to the approach angle e. The positioning bar 80 projects
through the frame 76.
1o The carriage body 78 of the pre-trial implant 79 (Fig. 70-73) can also
carry an
X-ray-visible marker 96.
For keeping the intervertebral space 62 (Fig. 64, 65) open for the discectomy
and/or for the insertion of an implant 5, 6, 7 or trial implant 9 or pre-trial
implant
79, according to the invention two struts 20, 21 (Fig. 81, 82) independent of
one
another and selectable from a group of leaf-like, different struts are formed,
the
two struts 20, 21 being wedge-shaped at the angle of lordosis in their
proximal
area and being medially curved at their proximal end.
2o The struts 20, 21 (Fig. 64, 65) may be toothed (Fig. 81, 82) in their
proximal
area 81 at their edges 82 facing the vertebrae and may have, at their distal
end,
a coupling device 83 (Fig. 79, 80) for direct or indirect connection to an
attachment frame 84, e.g. Synframe .
According to the invention, at least one of the two struts 20, 21 (Fig. 81,
82) is
bent medially in its distal area 85, when at least one of the two struts 20,
21 can
be formed with reduced height between its proximal and its distal area.
The two struts can be connected at their distal end 86 (Fig. 81, 82) by means
of
the connecting piece 87, and the connecting piece 87 can also be connected to
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a handle 86 - preferably by means of detachable coupling 89 (Fig. 79, 80).
The handle 86 of the struts 20, 21 may have guide elements 90 for lateral
support (Fig. 79).
According to the invention, an assembly tool 18 (Fig. 63a-e) is provided for
assembling an intervertebral disc implant according to the invention having a
superior and an inferior implant plate 5, 7 and an inlay 6. The assembly tool
18
has a baseplate 91 and a base 92 and a collet 93a,b in the base 92. The collet
1o 93a is formed for interlocking with an implant plate 5 or 7. A batten-like
guided
sliding element 94 which has an interlocking collet 93b for the inlay 6 is
coordinated with the base 92. The two implant plates 5, 7 and the inlay 6 can
be
placed in their collet in such a way that they are correctly positioned
relative to
one another and, after insertion of the sliding element 94, locked with one
another. The base 92 of the assembly tool and the sliding element 94 are
connected to one another in a slidable manner by means of parallel guide 95,
e.g. by pins 23a,b.
The intervertebral implant 5, 6, 7 (Fig. 10-14) for insertion into a superior
vertebra 1 and an inferior vertebra 2, having a superior part 5, an inferior
part 7
and an inlay 6, is designed, according to the invention, as an all-in-one
intervertebral implant 5, 6, 7 (Fig. 64, 65), and it can be inserted at 45 by
means of a left oblique anterior approach into a prepared groove 3, 4 in the
superior vertebra I or inferior vertebra 2 by means of an instrument 13 for
insertion at 45 . In the case of a variant according to the invention, the
intervertebral implant 5, 7 can be inserted without inlay 6, the inlay 6
subsequently being inserted using another instrument 16 for insertion at 450
(Fig. 97).
3o The prepared groove 3, 4 (Fig. 59, 60, 64) in the superior vertebra I or
inferior
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vertebra 2 makes an angle of 90 with the respective intervertebral surface in
order to permit the best possible retention according to the invention.
Using the instrument 13 (Fig. 33-35, 64-66) for inserting an intervertebral
5 implant 5, 6, 7 at 450, an intervertebral implant 5, 6, 7 comprising 3 parts
all in
one can be held and can be inserted at 45 by means of an oblique anterior
approach into the intervertebral space.
Using an alternative instrument 16 (Fig. 97) for inserting an intervertebral
io implant 5, 6, 7 at 45 , first the upper part 5 and lower part 7 of an
intervertebral
implant 5, 6, 7 can be held at about 45 and then the inlay 6 can be inserted
at
the same angle of about 45 by means of a left oblique anterior approach.
The components of the implant are preferably offered as a set in a
sterilizable
15 box.
EXAMPLE OF INDUSTRIAL APPLICATION
After opening of the abdominal cavity for an approach at 45 on the patient's
left
side, first the intervertebral disc is removed (discectomy) and the
intermediate
space is cleaned.
For maintaining the distance, the struts 20, 21 or the alternative variant of
the
struts 100, 101 can be inserted at this point. By tapping on the impact head
104
with recesses 105a,b for screwdriver 53 and impact pipe 106, the struts 100,
101 which are guided by the rails 107a,b can slide into the intervertebral
space.
A trial implant 9 (Fig. 20-23) is then inserted. Corresponding to the size of
the
vertebrae, the trial implant 9 is present in the set sizes M or L and the
various
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angles of lordosis. On the basis of his experience and through insertion of
different variants, the surgeon finds the optimum size.
The position of the implant is of considerable importance, and the trial
implant 9
is therefore exactly aligned by the surgeon with radiographic monitoring, by
tapping onto the notches 24a and 24b.
An adjustable stop 17 prevents the trial implant 9 from penetrating too far
into
the intervertebral space. By turning the adjusting screw of the adjustable
stop 17
by means of a screwdriver, the stopper can be turned forwards or backwards by
about 9 mm. A trial implant 9 which has been inserted a track too far can thus
1o be retracted again.
Alternatively, in order to find the exact middle for the implant, a pre-trial
implant
(Fig. 70-73), which is likewise aligned by means of X-ray monitoring, can be
used.
The shank 22 of the trial implant 9 is fixed on the Synframe , and only
thereafter
is the chisel 10 introduced into the slot of the trial implant 9, and the
upper or the
lower groove is chiselled into the upper or lower vertebra by tapping on the
impact head (Fig. 53-58).
2o The groove must be at right angles to the respective intervertebral surface
so
that the implant rests against the superior and inferior surface with
interlocking.
According to the invention, the surgeon leaves the chisel in the bone after
the
upper chiselling and then performs the lower chiselling with a second chisel
which results in better correspondence of the grooves with the implant keels.
After the upper and lower grooves have been chiselled in the bones (Fig. 61,
62), struts 20, 21 are introduced now at the latest to the left and right of
the trial
implant, unless they are already present, and the trial implant is removed.
3o The final implant 5, 6, 7 is now inserted (Fig. 67).
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There are 2 variants.
In the first one, the inlay is inserted only after the upper and lower implant
parts 5
and 7 have been pushed into the bone.
The insertion of an intervertebral implant 5, 6, 7 (Fig. 10-14) with
subsequent
insertion of the inlay 6 is effected using an instrument 16 (Fig. 97).
In the second "all-in-one" variant, the entire implant is inserted
immediately. The
insertion of an intervertebral implant 5, 6, 7 all in one is effected using an
1o instrument 13 (Fig. 33-35).
When the implant fits correctly, which is likewise monitored by means of X-
rays,
the struts 20, 21 according to the invention (Fig. 67, 81, 82) are removed and
the abdominal cavity is closed again by a conventional surgical method.
The spirit and scope of the appended claims should not be limited to the
description of the preferred versions contained herein. Many modifications may
be made in the techniques and structures described and illustrated herein
without departing from the spirit and scope of the invention. Accordingly, the
techniques and structures described and illustrated herein should be
understood to be illustrative only and not limiting upon the scope of the
present
invention. Particularly for the U.S. national stage, it should be understood
that
the original presentation of international-style claims and their subsequent
replacement in entry to U.S. national phase should not invoke any limitation
upon the scope of the claimed invention as defined by the U.S. claims
presented for examination, including known equivalents and unforeseeable
equivalents at the time of filing of this application.
